Method and apparatus for conducting total liquid ventilation with control of residual volume and ventilation cycle profile
A method of applying total liquid ventilation to a patient according to a ventilation cycle including inspiration and expiration profiles, comprises supplying oxygenated liquid to the patient's lungs, withdrawing liquid from the patient's lungs, and controlling independently supply of oxygenated liquid to the patient's lungs and withdrawal of liquid from the patient's lungs. This supply and withdrawal independent control comprises producing a ventilation cycle having independently controlled inspiration and expiration profiles. To carry out the method, a total liquid ventilator system comprises an inspiration pump for supplying oxygenated liquid to the patient's lungs, and an expiration pump for withdrawing liquid from the patient's lungs. A ventilation cycle control comprises first and second pump controllers connected to the inspiration and expiration pumps, respectively, to produce a ventilation cycle having independently controlled inspiration and expiration profiles.
1. A method of applying total liquid ventilation to a patient according to a ventilation cycle including inspiration and expiration profiles, comprising:
supplying oxygenated liquid to the lungs of the patient during inspiration, wherein supplying oxygenated liquid to the patient's lungs comprises accumulating oxygenated liquid from an oxygenator unit in an inspiration piston pump during expiration, and transferring the oxygenated liquid accumulated in the inspiration piston pump to the patient's lungs during inspiration;
withdrawing liquid from the patient's lungs during expiration, wherein withdrawing liquid from the patient's lungs comprises accumulating liquid from the patient's lungs in an expiration piston pump during expiration, and transferring the liquid accumulated in the expiration piston pump directly to the oxygenator unit during inspiration; and
controlling independently supply of oxygenated liquid to the patient's lungs and withdrawal of liquid from the patient's lungs, the supply and withdrawal independent control comprising producing a ventilation cycle having independently controlled inspiration and expiration profiles.
2. A method of applying total liquid ventilation as defined in claim 1 , further comprising:
simultaneously starting transfer of the oxygenated liquid accumulated in the inspiration piston pump to the patient's lungs and transfer of the liquid accumulated in the expiration piston pump to the oxygenator unit; and
extending a time of residence of the liquid in the oxygenator unit by transferring the liquid accumulated in the expiration piston pump to the oxygenator unit more rapidly than the oxygenated liquid accumulated in the inspiration piston pump is transferred to the patient's lungs.
3. A method of applying total liquid ventilation as defined in claim 1 , further comprising:
producing a pause between (a) transfer of the oxygenated liquid accumulated in the inspiration piston pump to the patient's lungs and transfer of the liquid accumulated in the expiration piston pump to the oxygenator unit, and (b) accumulation of oxygenated liquid from the oxygenator unit in the inspiration piston pump and accumulation of liquid from the patient's lungs in the expiration piston pump.
4. A method of applying total liquid ventilation as defined in claim 1 , further comprising:
producing a pause between (a) accumulation of oxygenated liquid from the oxygenator unit in the inspiration piston pump and accumulation of liquid from the patient's lungs in the expiration piston pump, and (b) transfer of the oxygenated liquid accumulated in the inspiration piston pump to the patient's lungs and transfer of the liquid accumulated in the expiration piston pump to the oxygenator unit.
5. A method of applying total liquid ventilation as defined in claim 1 , further comprising:
starting accumulation of liquid from the patient's lungs in the expiration piston pump before accumulation of oxygenated liquid from the oxygenator unit in the inspiration piston pump, and
simultaneously ending accumulation of oxygenated liquid from the oxygenator unit in the inspiration piston pump, and accumulation of liquid from the patient's lungs in the expiration piston pump.
6. A system for applying total liquid ventilation to a patient according to a ventilation cycle including inspiration and expiration profiles, comprising:
an inspiration pump for supplying oxygenated liquid to the lungs of the patient, wherein the inspiration pump comprises an inspiration piston pump for accumulating oxygenated liquid from the oxygenator during expiration, and for subsequently transferring the accumulated oxygenated liquid to the patient's lungs during inspiration; and
an expiration pump for withdrawing liquid from the patient's lungs, wherein the expiration pump comprises an expiration piston pump for accumulating liquid from the patient's lungs during expiration, and for subsequently transferring the liquid accumulated from the patient's lungs directly to the oxygenator during inspiration; and
a ventilation cycle control means comprising first and second pump controllers connected to the inspiration and expiration pumps, respectively, to control independently said inspiration and expiration pumps in order to produce a ventilation cycle having independently controlled inspiration and expiration profiles.
7. A system for applying total liquid ventilation as defined in claim 6 , wherein the first and second pump controllers comprise:
means for simultaneously starting transfer of the oxygenated liquid accumulated in the inspiration piston pump to the patient's lungs and transfer of the liquid accumulated in the expiration piston pump to the oxygenator unit; and
means for extending a time of residence of the liquid in the oxygenator unit by transferring the liquid accumulated in the expiration piston pump to the oxygenator unit more rapidly than the oxygenated liquid accumulated in the inspiration piston pump is transferred to the patient's lungs.
8. A system for applying total liquid ventilation as defined in claim 6 , wherein the first and second pump controllers comprise:
means for producing a pause between (a) transfer of the oxygenated liquid accumulated in the inspiration piston pump to the patient's lungs and transfer of the liquid accumulated in the expiration piston pump to the oxygenator unit, and (b) accumulation of oxygenated liquid from the oxygenator unit in the inspiration piston pump and accumulation of liquid from the patient's lungs in the expiration piston pump.
9. A system for applying total liquid ventilation as defined in claim 6 , wherein the first and second pump controllers comprise:
means for producing a pause between (a) accumulation of oxygenated liquid from the oxygenator unit in the inspiration piston pump and accumulation of liquid from the patient's lungs in the expiration piston pump, and (b) transfer of the oxygenated liquid accumulated in the inspiration piston pump to the patient's lungs and transfer of the liquid accumulated in the expiration piston pump to the oxygenator unit.
10. A system for applying total liquid ventilation as defined in claim 6 , wherein the first and second pump controllers comprise:
means for starting accumulation of liquid from the patient's lungs in the expiration piston pump before accumulation of oxygenated liquid from the oxygenator unit in the inspiration piston pump, and
means for simultaneously ending accumulation of oxygenated liquid from the oxygenator unit in the inspiration piston pump, and accumulation of liquid from the patient's lungs in the expiration piston pump.